Memorization is probably one of the most fundamental aspects of learning a foreign language. Indeed, our brain is naturally not very good at remembering new information, that’s why it’s necessary to optimize this exercise with effective techniques. Spaced repetition is one of them and recent technological advances regard it as an essential means of learning vocabulary. So let’s see why this wonderful tool will make you say goodbye to your blackouts.


What is spaced repetition?

SRS (Spaced Repetition System) is a learning technique based on revisions of regular intervals, which are more or less spaced: the more the word to learn is anchored in your memory, the more the revisions will be distant from each other.

Efficient, but not magic…

I wanted to present you this tool for two reasons: first of all, because it’s extremely powerful and I use it every day. Secondly, it’s getting very popular among language learners these days, becoming a real El Dorado for some. There are always new services and applications appearing, promising you will learn a language in record time thanks to a “scientific method”. Most of the time, this method is nothing else than a spaced repetition algorithm.

Since my objective is also to help you develop your critical thinking towards language courses, I thought a short clarification could be needed.


The principles of forgetfulness and memory

The forgetting curve of Ebbinghaus and how to counter it

Hermann Ebbinghaus is a German psychologist of the 19th century. He developed the forgetting curve which represents how fast we forget the information we learn.

Because it wants to avoid any useless overload, our brain constantly and exponentially forgets things he receives but which he finds unnecessary. Maybe you’ve spent one hour learning a long list of vocabulary: that’s a great thing, but unfortunately, you will have forgotten more than half of it after a few hours and almost all of it after a few days.

When you don’t revise, the information disappears very quickly from your memory. Conversely, each revision session make you forget more slowly.

Fortunately, forgetting isn’t an inevitable thing, and it’s possible to make your brain understand that yes, the French word for “slippers” is a very important information. For this, Ebbinghaus advocates two things:

  • A better representation of the element you learned, thanks to associations of ideas, which are also known as mnemonics. When you learn a word with its pronunciation and an image representing it, you will remember it more easily. It’s the same thing with small tips like “FANBOYS” to remember the coordinating conjunctions in English (For, And, Nor, But, Or, Yet, So).
  • Regular and spaced repetitions, which make you forget more and more slowly. The more you remember an information, the more time between each repetition there will be.

To have a better memorization, it’s thus important to first strongly anchor the information into your mind while using all the means you have access to (images, sounds, catchphrases…), and then to repeat it regularly just before forgetting it.

Some expressions are literraly enrooted in my mind because I managed to find the appropriate mnemonic for me. For example, the Chinese word 龙 (lóng), which means “dragon”. I’ve associated that word to the adjective “long” because Chinese dragons are long creatures. So I’m not going to forget this word (at least orally) just with this simple pun.

Flashcards and the Leitner system

Sabastian Leitner was a German journalist and the author of the book “How to learn to learn”. The Leitner system is based on the use of flashcards which are generally cardboards having on their front part a question about the information to learn, and on the back the actual information. When you learn a language, you can write the word in English on the front and its translation on the back, or the opposite, depending on which order you prefer learning (English to French, or French to English).

In the Leitner system, flashcards are ranked in three or five different boxes, on an ascendant order of knowledge. In the first box, you put the cards you don’t know at all and in the last one, the ones you remember the most. This system uses spaced repetition, that’s why you revise the cards of the 1st box very frequently, the ones of the 2nd box a bit less and so on. At each revision session, if you recognize the card you picked, you put it in the next box. If not, you put it back in the 1st box or the preceding box, depending on which version of the Leitner system you use.

In the end, your goal is to pass all the cards in the last box and to make them stay there. As you repeat this process over and over, with more space in time between the sessions, the information will enter your long term memory and you won’t need to revise them for a very long time.

An efficient system in theory, but quite complicate to use practically

So now you understand how spaced repetition works. It’s a very effective technique because it’s suitable for your brain. However, it has a big disadvantage: it’s very complex to implement it. In order to use it the right way, you would have to calculate the necessary length of time between each repetition for each flashcard, and to set an appropriate planning of your future revision sessions afterwards. That would be worse than a nightmare.

The creator of the famous Pimsleur method, the American Paul Pimsleur, has set a simpler scale of revisions: his intervals are 5 seconds, 25 secondes, 2 minutes, 10 minutes, 1 hour, 5 hours, 1 day, 5 days, 25 days, 4 months and 2 years. This technique might be useful to remember one important information, such as a credit card or telephone number, but it would be difficult to use it for hundreds of vocabulary words… That’s where computing science intervenes, to make this tedious work automatic. Progress, my friends!


Learning vocabulary with a SRS software

An SRS software calculates the revision intervals for you for each flashcard and make you revise a word when you are just about to forget it. You considerably save time.

The origins: Woźniak algorithm, re-used several times

Piotr Woźniak was a Polish student in molecular biology in the 80s. He developed an algorithm to help him learn English more efficiently. This algorithm gave birth to SuperMemo, a software still used today. This algorithm has been re-used in other software, such as Anki, MosaLingua or Mnemosyne. You could even dare to say that every software using spaced repetition today comes more or less directly from Woźniak’s algorithm.

Which material: computer or smartphone?

There was a time when SRS software could be used only with computers. Nowadays, they have made their entry on phones and tablets. I find smartphones particularly adapted for SRS, because they go back to the simplicity of the flashcard system. You can hold them in your hand, it’s very intuitive thanks to the touch interface and you can bring it everywhere: you can revise every time you have some spare time like in public transports, waiting in line…

Unless you hate smartphones or don’t have one or a tablet, I suggest you to download a spaced repetition app. Anyway, most of them are also available on computers and it’s possible to synchronize your devices: that means you can start a revision session at home on your computer and continue it later while you’re waiting for the bus.

Some SRS software and app

I’m not going to compare all of these software for three reasons. First, there are too many and I don’t know all of them. Second, they don’t always work the same way (some uses flashcards and others don’t) and I’ve never tried to compare them before. Then, you should know that all the main market players, from Rosetta Stone to Duolingo, as well as Babbel, use SRS in some way.

I made a small selection of three SRS software which should be fairly representative of the others. They can be your gateway to the world of SRS software. The prices are indicative for May 2018 and they might change in the future.


Medium: computer (Windows, Mac, Linux), smartphone (Android, iOS, Blackberry)

Price: free, except for iOS  ($24.99)

Strong point: it fits all needs


It might be the most famous. Anki has the advantage of being very flexible and allows you to create and import flashcard decks. The creation of cards is pretty rich since it’s possible to add sounds and images. The AnkiWeb service enable to revise with different devices having access to Internet.

Despite a program doing its job very well, the disadvantage of Anki is its user experience. And note that while the Android version of Anki is free and developed by an independent team, the iOS version costs $24.99. This high price enables to finance the other free versions of Anki.


Medium: computer (from an internet browser), smartphone (Android and iOS)

Price: free, with a premium subscription ($4.92 per month or $129 for life)

Strong point: it has lots of courses available


Memrise uses a system mixing flashcards and quizzes (listening, translating, writing…). Cards are often accompanied by mems, which are usually funny wordplay mnemonics…

In addition to its pleasant interface, Memrise benefits from a huge community creating its own shared courses. In fact, the courses are not limited only to languages: you can also learn all the French departments and regions but also cooking tips or even all the names of the Pokemons. Finally, I really like how the way you learn words is represented on Memrise: you plant a seed and water it at each revision session until you get a flower. It’s a very poetic and above all very meaningful metaphor.


Medium: computer (MosaLingua Web service), smartphone (Android and iOS)

Price: $4.99 for the smartphone apps, and $49.90 per year for MosaLingua Web

Strong point: it’s very complete and pleasant to use


MosaLingua has a nice interface and a very complete content. Flashcards are often accompanied with images, audio files, examples, and they even offer the possibility to register. You can also create your own cards, even though this feature is not as prominent as in Anki.

The company recently launched an Internet browser version, MosaLingua Web. It seems very rich and interesting but I haven’t tried it, so I cannot really comment on its effectiveness.

Find the SRS software that suits you best

These three software represent just a limited number of all the software and apps using spaced repetition. You could also use another one, depending on your tastes.